Fears radiation will spread from Japan to Calif.

The fear that radiation will spread from Japan to the U.S. has sparked a run on potassium iodide pills, even though experts say that the threat of exposure is very remote.

Every year we are all exposed to some level of radiation, 3.5 millisieverts, which is equivalent to about 67 chest X-rays or 134 cross-country flights. The radiation at the affected level in Japan is around 400 millisieverts by comparison. When someone reaches 1,000 millisieverts, radiation sickness sets in, and a fatal dose is around 5,000 millisieverts.

Experts said California hasn't absorbed any of that radiation, yet potassium iodide, the pill that saturates your thyroid to protect you from exposure, is selling out store to store in the state. Some people are also going online to get their hands on Geiger counters.

Health officials in Los Angeles County said there is a minimal risk of harmful exposure and that buying potassium iodide right now is not necessary.

"I think there is no reason for people to go out and buy potassium iodide now," said Dr. Jonathan Fielding, director of the Los Angeles County Department of Public Health. "And there are good reasons not to take it. It can cause allergic reactions, intestinal upset, salivary gland problems. I understand the impulse, but I think sometimes it is important to resist it."

With the recent nuclear reactor explosions in Japan, health officicals also reminded the public that local and federal agencies are continually monitoring levels of radiation in our air, food and water supply.

San Francisco resident Bill Malinowski said he is concerned about the risk. While he is not buying potassium iodide, he is keeping a close eye on the weather.

"It is scary that I live in Northern California right on the coast," said Malinowski. "So perhaps the prevailing winds push some of that radiation fallout."

Other people said that they understand the precaution, but are not worried about exposure.

"They're fearful I guess," said Santa Monica resident Tawny Simms. "If it's my time, it's my time; one way or the other."

If you have concerns about radiation, you can call the California Department of Public Health hotline at (916) 341-3947. It is open 24 hours a day, seven days a week, and provides answers in English and Spanish.